Park Ranger Stuart Greeter leads our small troop of nature lovers through the dense forest of Congaree National Park at a comfortable pace, even stopping occasionally to point out wildflowers and wildlife tracks, but it’s clear he’s a man on a mission.

He wants us to see the trees.

The park is home to at least 25 champion trees, judged by naturalists as the largest living examples of their species, and several times a year, Greeter guides visitors on a "Big Tree Hike” for an up-close look at the ancient oaks, elms, maples and pines.

“If you want to see what mature, old-growth forests looked like before Europeans came to this land, come visit this park,” he says as we make our way through a portion of the sprawling 27,000-acre tract, one of the last remaining floodplain forests in North America.

Several hours into the trek, Greeter leads us to a 170-foot-tall loblolly pine and pulls a tape measure from his day pack. It takes three of us literally hugging the tree to wrap the tape tight and low around the massive trunk and read the results: 15 feet around. “That’s the biggest loblolly in the country,” Greeter says, not bothering to conceal his enthusiasm for this national treasure.

The tree hike is just one of the free, ranger-led excursions offered in Congaree National Park. Other nature outings include butterfly counts, bird watching expeditions and nighttime hikes called “owl prowls”—all of which explore the diverse plant and animal life of South Carolina’s only national park. Visitors can also take self-guided tours on more than 20 miles of hiking trails and 2.4 miles of boardwalks that explore the natural and human history of the Congaree swamp.

South Carolina was once home to millions of acres of towering pines and huge hardwood trees similar to the ones found in Congaree National Park. Around the turn of the 20th century, lumber companies purchased vast areas of land throughout the state and spent the next two decades harvesting timber along the Santee and Congaree river systems.

Ironically, the woodsmen left the largest trees untouched. They were simply too big to remove once felled. At the close of the 1960s, however, owners of timber-rich floodplain land started looking at new ways of harvesting the trees they’d missed. It was only then that environmental organizations and concerned citizens—inspired by outdoor writer Harry Hampton, the “founding father” of the state’s conservation movement— began working to protect the floodplain forests.

Their efforts paid off in 1974 with Congaree Swamp being designated a National Natural Landmark. Two years later, Congress provided further protection when it established the area as the Congaree Swamp National Monument. And finally, in 2003, Congress upgraded the national monument to Congaree National Park.

Today, the history of the area is preserved in the exhibits of the Harry Hampton Visitor Center, located at the park’s entrance near Gadsden. The building also serves as the starting and ending point for all of the ranger-led excursions, including guided canoe trips along Cedar Creek, a beautiful stretch of black water that flows lazily through a 130-foot-tall canopy of bald cypress and water tupelo trees.

On a recent morning paddle, park volunteer John Galbary helped lead a group of more than a dozen outdoor enthusiasts. A retired life sciences teacher, he would stop paddling often to lean back in his kayak and point out the abundant wildlife hiding in plain sight.

At one point in the trip, Galbary showed us a fat, three-and-a-half-foot cottonmouth resting at the base of a water tupelo tree. Further along the creek, he told us to look up at the brown water snake sunning itself on a branch overhead. Nothing escaped his keen eye, including the numerous golden orb weaver spiders standing guard over their intricately constructed webs and the extensive areas of creek bank torn up by wild hogs looking for their next meal.

Galbary has made this trip at least 150 times before, but the swamp never fails to amaze him, he says. “When you come to Congaree you experience all of the wonders and beauties and splendors of a living earth.”